In vacuum cleaners employing a floor cleaning means and an off the floor cleaning means, it is common to provide two modes of vacuum operation, i.e., floor vacuuming and an accessory cleaning tool, by way of a valving mechanism. Flap valves and some rotary valve arrangements have typically been used for vacuum stream control in this regard. These arrangements have not, however, been generally designed to accommodate the concerns of avoiding fouling by materials entrained in the vacuum stream, allowing for consumer accessibility and visibility to check for possible clogging, and further providing for throttling between floor cleaning and hose cleaning modes to allow for cleaning delicate subjects via reduced velocity at the suction ends of the appliance without varying the vacuum motor speed.
For example, there is described in U.S. Pat. No. 1,887,600 a rotary diverter valve which is transparent for viewing purposes and located at the T-shaped juncture of vacuum lines with an axis of rotation parallel to the main vacuum line. Upon rotation of the valve, a port in the cylindrical valve wall opens one of the dirty air lines and correspondingly closes the other line. U.S. Pat. No. 1,533,271 also discloses such a valve. This latter valve operates to divert the vacuum streams from either the floor cleaning member or the hose nozzle member, but does not allow for a combination thereof. The valve viewing panel, although initially clear, is also subject to abrasion over continuous use because the viewing panel forms part of the diverting elbow for the dirty air stream, and is therefore abraded by material entrained in the vacuum stream, and thus its long term function is jeopardized.
In U.S. Pat. No. 2,504,846 an opaque rotary diverter valve is located in a junction of vacuum lines with an axis of rotation parallel to the main vacuum line. The valve has an arcuate peripheral opening extending through nearly half the circumference of the valve which may be used to direct the vacuum to one of two dirty air lines. Even if this valve is changed to a clear material, its configuration suffers from the same disadvantage of only short term visibility through the viewing panel as the previously discussed valve, because the viewing panel forms part of the diverting elbow.
Other rotary diverter valves known in the art are somewhat inaccessible to the consumer in cases of plugging or partial clogging of the device (see FIGS. 1 & 2 discussed in more detail hereafter).